Biology Questions 1…?

1. What is the definition of an oxidation reaction? A reduction reaction? What molecules serve as shuttles for the products of oxidation/reduction reactions? What types of biological molecules are generally oxidized compounds? Reduced?
2. What is the overall chemical equation for the breakdown of glucose to CO2 + H2O? What are the three major steps in this chemical process? Where does each step take place in the cell? How is the energy ultimately used?
3. What is the function of NAD+ and FAD?
4. Outline the process of glycolysis. Know the 2 major steps of glycolysis, the starting and ending products of each step, the reaction, and the energy use or yield for each step. What types of biomolecules besides carbohydrates enter the ATP synthesis pathway during glycolysis?
5. How is pyruvate modified before it enters the citric acid cycle? Why is this important? Where does this take place?

1) Oxidation describes the loss or electrons by a molecule, atom or ion.
Recuction describes the gain of electrons by a molecule, atom or ion.
Respiration involved oxidising glucose.
Electron carriers become reduced molecules.
2) C6H1206 + 6O2 —> 6CO2 + 6H20 + energy.
2 major steps are glycolysis in cytoplasm, link reaction and Krebs cycle (both in the matrix of mitochondria). The energy is used for respiration, or for muscle contractions.. or basically any chemical reaction in a cell.. ATP is the molecular currency of cells.. it supplies the cell with the energy it needs to work.
3) NAD and FAD are electron carriers, they become reduced and take H+ to the electron transport chain which converts the majority of ADP back to ATP releasing energy.
4) A molecule of glucose is broken down into two molecules of pyruvate (3 carbon compound). 2 ATP molecules are used, and 4 are made, making a net gain of 2 ATP molecules. The glucose is lysed into 2 molecules of glyceraldehyde 3-phosphate. 2 NADS are reduced for each glucose split.
5) In the link reaction pyruvic acid is converted into acetyl coenzyme A, this happens ONLY is oxygen is present. This happens in the matrix of a mitochondrion. This is essential because in Krebs Cycle, the Acetyl CoA combines with the oxaloacetic acid to make citric acid (a 6 carbon compound) where it is broken down releasing hydrogen ions to be taken up by NAD (and later H+ ions taken up also by FAD).

That;s all i can do off the top of my head… hope it helps a lil..

Lec 7 | MIT 7.014 Introductory Biology, Spring 2005